1. Field of the Invention
The present invention relates to a control apparatus and a control system, and more particularly to a control apparatus having a communication unit for conducting the data communication, and a control system including a plurality of control apparatuses connected to communicate with each other.
2. Description of the Related Art
In recent years, a vehicle is mounted with various control units including an engine control unit for controlling the fuel injection or ignition timing of the engine, an ABS control unit for controlling an anti-lock brake system (ABS), and an air bag control unit for controlling the expanding operation of an air bag.
Also, a control system equipped with a so-called vehicle LAN in which these control units are connected via a communication line has been introduced. For example, a sensor signal detected by the engine control unit is sent via the communication line to another control unit (ABS control unit, etc.), which then can conduct efficient control utilizing the received sensor signal.
By the way, many of troubles in the control units occurs intermittently while driving or don't continue. Usually, these control units have a function of storing content of the trouble in a memory through the self-diagnosis.
In a service factory of dealers, when a trouble occurs, a specific reader is connected to a control unit to read a self ID code or a trouble code stored in the memory of the control unit, and read an exchange and repair history of the control unit or diagnose the trouble content with reference to a database for ID code or trouble code possessed by the dealers.
However, because the general used vehicle shops that are not the dealers could not refer to the above database, there was a problem that the information of exchange and repair history of individual control apparatuses mounted on the vehicle could not be directly confirmed.
Also, the information of the ID code regarding the control apparatus, which is mounted to a vehicle at present, is only stored in the memory of the control apparatus. Thus, when a new control apparatus is mounted due to a failure, the information about the control apparatus previously mounted necessarily disappeared without leaving information that the control apparatus was exchanged. As a result, there is a problem that the exchange and repair history cannot be correctly grasped.
Also, because the information of the exchanged control apparatus in the memory might be rewritten incorrectly by a dedicated writing device, there is a problem that the correct exchange and repair history is difficult to grasp.